Newark Mayor Cory Booker has a 43-point lead over his closest competitor in a 2014 Democratic primary for New Jersey’s Senate seat, a new poll shows.

Half of all Democratic voters in New Jersey said they would back Booker in a primary, compared to just 7 percent for Rep. Frank Pallone and 4 percent for Rep. Rush Holt. About a third of Democratic primary voters are undecided, according to the Fairleigh Dickinson University poll.

Sen. Frank Lautenberg, a Democrat, announced his retirement last month, after Booker said he was exploring a run for the seat. Booker’s early announcement led to harsh sparring between the 43-year-old mayor and the 89-year-old World War II veteran.